FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal

Rev. 1.2

Feb. 2009

Page 9 of 21

Register Description

Address

Description

0Eh

Alarm & WP Control

D7

D6

D5

D4

D3

D2

D1

D0

AL/SW

F1

F0

WP1

WP0

VBC

FC

TST

AL/SW

Alarm/Square Wave Select: When set to 1, the alarm controls the ACS pin as well as the AF flag. When set to 0,

the selected Square Wave Freq will be driven on the ACS pin, and an alarm match only sets the AF flag. Battery-

backed, read/write.

F(1:0)

Square Wave Freq Select: These bits select the frequency on the ACS pin when the CAL and AL/SW bits are

both 0. Battery-backed.

Setting

F(1:0)

Setting

F(1:0)

1 Hz

00 (default)

4096 Hz

10

01

32768 Hz

11

WP1,WP0

Write Protect. These bits control the write protection of the memory array. Battery-backed, read/write.

Write-Protect addresses

WP1

WP0

None

0

0

Bottom 1/4

0

1

Bottom 1/2

1

0

Full array

1

1

VBC

VBAK Charger Control: Setting VBC to 1 (and FC=0) causes approx. 80 µA (1mA if FC=1) trickle charge

FC

Clearing VBC to 0 disables the charge current. Battery-backed, read/write.

TST

Invokes factory test mode. Users should always set this bit to 0.

0Dh

Alarm – Month

D7

D6

D5

D4

D3

D2

D1

D0

M

0

0

10 Month

Month.3

Month.2

Month.1

Month.0

Contains the alarm value for the month and the mask bit to select or deselect the Month value.

/M

Match. Setting this bit to a ‘0’ causes the Month value to be used in the alarm match logic. Setting this bit to a

‘1’ causes the match circuit to ignore the Month value. Battery-backed, read/write.

0Ch

Alarm – Date

D7

D6

D5

D4

D3

D2

D1

D0

M

0

10 date.1

10 date.0

Date.3

Date.2

Date.1

Date.0

Contains the alarm value for the date and the mask bit to select or deselect the Date value.

/M

Match: Setting this bit to a ‘0’ causes the Date value to be used in the alarm match logic. Setting this bit to a ‘1’

causes the match circuit to ignore the Date value. Battery-backed, read/write.

0Bh

Alarm – Hours

D7

D6

D5

D4

D3

D2

D1

D0

M

0

10 hours.1

10 hours.0

Hours.3

Hours2

Hours.1

Hours.0

Contains the alarm value for the hours and the mask bit to select or deselect the Hours value.

/M

Match: Setting this bit to a ‘0’ causes the Hours value to be used in the alarm match logic. Setting this bit to a ‘1’

causes the match circuit to ignore the Hours value. Battery-backed, read/write.

0Ah

Alarm – Minutes

D7

D6

D5

D4

D3

D2

D1

D0

M

10 min.2

10 min.1

10 min.0

Min.3

Min.2

Min.1

Min.0

Contains the alarm value for the minutes and the mask bit to select or deselect the Minutes value

/M

Match: Setting this bit to a ‘0’ causes the Minutes value to be used in the alarm match logic. Setting this bit to a

‘1’ causes the match circuit to ignore the Minutes value. Battery-backed, read/write.